The present invention relates to an electric motor operated adjustment drive, particularly for the utilization in mobile processing machines.
Linear adjusting drives are known in which an adjustment member is formed as a solid rod or a pipe with a closed end located in the working space of the drive. In such drive, during retracting and extending of the adjustment member, a relatively great volume variation of the working space takes place, the working space being formed by the adjustment stroke and the entire transverse surface of the adjustment member described by the outer profile of the same. In electric motor operated adjustment drives the working space which receives the adjustment member is not filled with a working fluid as in hydraulic or pneumatic drives. In such adjustment drives, a relatively great air exchange between the working space and the surrounding atmosphere takes place which can lead to a premature dirtying of the drive when it operates in wet, dusty, or the like dirty atmosphere. The parts of the drive can wear out relatively fast, whereby the required adjustment position cannot be exactly attained under the action of vibrations, such as for example vibrations of the machine.